Published October 29, 2021 | Version v1
Dataset Open

High energy barriers for edge dislocation motion in body-centered cubic high entropy alloys

  • 1. Laboratory for Multiscale Mechanics Modeling, Institute of Mechanical Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
  • 2. Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, 9747 AG Groningen, The Netherlands

* Contact person

Description

Recent theory proposes that edge dislocations in random body-centered cubic (BCC) high entropy alloys have high barriers for motion, conveying high strengths up to high temperatures. Here, the energy barriers for edge motion are computed for two model alloys, NbTaV and MoNbTaW as represented by interatomic potentials, using the Nudged Elastic Band method and compared to theoretical predictions. The average magnitude of the barriers and the average spacing of the barriers along the glide direction agree well with the analytical theory, with no adjustable parameters. The evolution of the barriers versus applied stress is modeled, and the mean strength is in reasonable agreement with the predicted zero-temperature strength. These findings validate the analytic theory. A reduced analytic model based on solute misfit volumes is then applied to Hf-Mo-Nb-Ta-Ti-Zr and Mo-Nb-Ta-Ti-V-W alloys, rationalizing the observed significant strength increases at room temperature and 1000 ∘C upon addition of solutes with large misfit into a base alloy. The analytic theory for edge motion is thus a powerful validated tool for guiding alloy selection.

Files

File preview

files_description.md

All files

Files (353.0 MiB)

Name Size
md5:690ba1f4d334f479ade3bd7b32a4a275
259 Bytes Preview Download
md5:2583f2689d35e3bcfdd59ed19324df8c
353.0 MiB Download
md5:80396914cf89b6c03fd320803ca8de50
708 Bytes Preview Download

References

Journal reference
R.E. Kubilay, A. Ghafarollahi, F. Maresca, W.A. Curtin, npj Comput Mater 7, 112 (2021)., doi: 10.1038/s41524-021-00577-7